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On the stereochemistry of 1,4‐diheterocyclanes. IV —carbon‐13 NMR spectra and structural properties of 1,4‐dioxane‐2,3‐diols and their methyl‐substituted derivatives
Author(s) -
Äyräs Pertti
Publication year - 1978
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270110312
Subject(s) - chemistry , substituent , chemical shift , spectral line , stereochemistry , carbon 13 nmr , methyl group , homogeneity (statistics) , proton nmr , nmr spectra database , crystallography , group (periodic table) , organic chemistry , physics , astronomy , statistics , mathematics
The 1,4‐dioxane‐2,3‐diols and a number of their methyl‐substituted derivatives were synthesized and their 13 C NMR spectra measured. The configurational properties were studied on the basis of the spectral data and chemical equilibration. For the parent compound the trans configuration is slightly more stable. The hydroxyl groups are predominantly axial. Introduction of a methyl group at the 2 position causes the cis configuration of the hydroxyl substituents to become more stable. The substituent effects on the chemical shifts were calculated and used to test the conformational homogeneity of the compounds. The results indicate a biased (chair) conformation for all the methyl‐substituted derivatives which were studied. Methyl groups have strongly predominating equatorial orientation in each case studied.